Polarization rotation is key for modern optics but achieving it at mid-infrared frequencies is challenging and requires very thick phase retarders. Here, α-MoO3 flakes provide mid-infrared phase retardation and 90 degrees polarization rotation within one micrometer of material, a thickness ten times thinner than the operational wavelength.
- Michael T. Enders
- Mitradeep Sarkar
- Georgia T. Papadakis